通常应用程序在处理触摸事件时一般会用到motionevent.getAction()来判断上报的触摸点是ACTION_DOWN、ACTION_MOVE或ACTION_UP，然后做出移动、缩放等处理逻辑。每一个触摸点属性是在哪里定义的呢？是驱动上报就标记了每个点的触摸属性吗？
直接给结论：对于触摸点的属性，在InputReader中的dispatchTouches()函数中定义，而不是驱动给的。
void TouchInputMapper::dispatchTouches(nsecs_t when, uint32_t policyFlags) { BitSet32 currentIdBits = mCurrentCookedPointerData.touchingIdBits; BitSet32 lastIdBits = mLastCookedPointerData.touchingIdBits; int32_t metaState = getContext()->getGlobalMetaState(); int32_t buttonState = mCurrentButtonState; if (currentIdBits == lastIdBits) { if (!currentIdBits.isEmpty()) { // No pointer id changes so this is a move event. // The listener takes care of batching moves so we don't have to deal with that here. dispatchMotion(when, policyFlags, mSource, AMOTION_EVENT_ACTION_MOVE, 0, metaState, buttonState, AMOTION_EVENT_EDGE_FLAG_NONE, mCurrentCookedPointerData.pointerProperties, mCurrentCookedPointerData.pointerCoords, mCurrentCookedPointerData.idToIndex, currentIdBits, -1, mOrientedXPrecision, mOrientedYPrecision, mDownTime); } } else { // There may be pointers going up and pointers going down and pointers moving // all at the same time. BitSet32 upIdBits(lastIdBits.value & ~currentIdBits.value); BitSet32 downIdBits(currentIdBits.value & ~lastIdBits.value); BitSet32 moveIdBits(lastIdBits.value & currentIdBits.value); BitSet32 dispatchedIdBits(lastIdBits.value); // Update last coordinates of pointers that have moved so that we observe the new // pointer positions at the same time as other pointers that have just gone up. bool moveNeeded = updateMovedPointers( mCurrentCookedPointerData.pointerProperties, mCurrentCookedPointerData.pointerCoords, mCurrentCookedPointerData.idToIndex, mLastCookedPointerData.pointerProperties, mLastCookedPointerData.pointerCoords, mLastCookedPointerData.idToIndex, moveIdBits); if (buttonState != mLastButtonState) { moveNeeded = true; } // Dispatch pointer up events. while (!upIdBits.isEmpty()) { uint32_t upId = upIdBits.clearFirstMarkedBit(); dispatchMotion(when, policyFlags, mSource, AMOTION_EVENT_ACTION_POINTER_UP, 0, metaState, buttonState, 0, mLastCookedPointerData.pointerProperties, mLastCookedPointerData.pointerCoords, mLastCookedPointerData.idToIndex, dispatchedIdBits, upId, mOrientedXPrecision, mOrientedYPrecision, mDownTime); dispatchedIdBits.clearBit(upId); } // Dispatch move events if any of the remaining pointers moved from their old locations. // Although applications receive new locations as part of individual pointer up // events, they do not generally handle them except when presented in a move event. if (moveNeeded) { ALOG_ASSERT(moveIdBits.value == dispatchedIdBits.value); dispatchMotion(when, policyFlags, mSource, AMOTION_EVENT_ACTION_MOVE, 0, metaState, buttonState, 0, mCurrentCookedPointerData.pointerProperties, mCurrentCookedPointerData.pointerCoords, mCurrentCookedPointerData.idToIndex, dispatchedIdBits, -1, mOrientedXPrecision, mOrientedYPrecision, mDownTime); } // Dispatch pointer down events using the new pointer locations. while (!downIdBits.isEmpty()) { uint32_t downId = downIdBits.clearFirstMarkedBit(); dispatchedIdBits.markBit(downId); if (dispatchedIdBits.count() == 1) { // First pointer is going down. Set down time. mDownTime = when; } dispatchMotion(when, policyFlags, mSource, AMOTION_EVENT_ACTION_POINTER_DOWN, 0, metaState, buttonState, 0, mCurrentCookedPointerData.pointerProperties, mCurrentCookedPointerData.pointerCoords, mCurrentCookedPointerData.idToIndex, dispatchedIdBits, downId, mOrientedXPrecision, mOrientedYPrecision, mDownTime); } }}